The present invention relates to a power transmission belt or roller, and more particularly, it relates to a power transmission belt or roller including short fibers in a surface in contact with an opposite member such as a pulley.
In general, when a power transmission belt is splashed with water, the water intrudes into a space between the belt and a pulley, and the belt slips so that an unpleasant noise can be caused or a load cannot be sufficiently transmitted. For example, in a power transmission belt used as a fan belt for an automobile, the belt is splashed with water when the automobile runs through a puddle, resulting in causing the aforementioned phenomena.
Therefore, in order to remove water splashed on a belt, a conventional belt is provided with a concave cog latitudinally extending on the surface of the belt in contact with a pulley, or provided with a drain hole penetrating from the contact surface (the inner face) to the back face.
On the other hand, as is disclosed in, for example, Japanese Laid-Open Patent Publication No. 59-65644, it is known that the wear resistance of a belt can be improved by mixing short fibers such as carbon fibers in the contact surface with a pulley.
However, when a belt has the contact surface with a pulley including short fibers as described above, the short fibers can be exposed on the surface of the belt. In such a case, when the belt is splashed with water, the water can easily remain between the exposed fibers, and hence, the water is more difficult to remove than in a belt not including the short fibers. In particular, when the contact surface with a pulley is processed with a grindstone, the short fibers are more largely exposed, so that a water removing property can be further degraded, and the belt slips for a long period of time with a large noise. Moreover, when the belt is new, the short fibers are more largely exposed, and hence, the new belt has a poorer water removing property than a belt used for a long period of time.
Therefore, such a belt including the exposed short fibers can be provided with a cog or a drain hole as in the aforementioned conventional belt. However, this countermeasure requires a larger number of processing procedures, resulting in increasing a manufacturing cost. In addition, in providing a cog, a large number of cogs are necessary to be formed with a small pitch therebetween for attaining a sufficient water removing effect. Therefore, the belt can be degraded in its durability and a whistling noise can be caused. On the other hand, in providing a drain hole, the drain hole cuts a cord buried for enforcing the belt, so that the strength of the belt can be decreased.
Also in a power transmission roller including short fibers in a surface in contact with an opposite member, the water removing property is poor as in the power transmission belt. When the roller is splashed with water, the roller can slip so that an unpleasant noise can be caused and that a load cannot be sufficiently transmitted.
The object of the invention is improving means for removing water from a power transmission belt or roller including short fibers in a surface in contact with an opposite member, while suppressing the performance of the belt or roller from being degraded and the manufacturing cost from increasing. In addition, the water removing property against water splashed on the belt or roller is improved so that the belt or roller can be prevented from slipping and causing an unpleasant noise.